Compressed air and underpressure supply unit

ABSTRACT

A supply unit for providing compressed air and reduced pressure for dental surgery comprising several superimposed supply components including at least a compressor unit and a suction unit each unit containing a base plate and a cover plate and vertical posts that connect these plates as well as wall panels.

The invention refers to a compressed air and underpressure supply unitfor dental surgeries.

Such a supply unit is described in U.S. Pat. No. 3,553,840. In this unitthe compressor and the suction unit are mounted in a mobile frame whichalso carries the compressed air and underpressure consumers, i.e. asaliva remover and a hand-piece providing compressed air. This supplyunit represents an emergency supply and disposal unit for a dentalsurgery which is self-contained, apart from the electrical connectionrequired. No connections to fixed lines in the building are required.

Compressed air and underpressure in dental surgeries which are inconstant use are provided partly through lines fixed to the treatmentchair and partly through lines laid in the building. Normally acompressor and a suction unit are installed separately in the cellar ofthe relevant building and connected to the workplace through acompressed air line or an underpressure line. These installations areoften fitted by local tradesmen who have no special experience in therelevant field involved. Thus flexible parts of the underpressure lineare often laid incorrectly, for example, so that they partly collapse inunderpressure during operation and thus only part of the capacityprovided by the suction unit is available at the workplace.

This invention is therefore intended to provide a supply unit which canbe pre-assembled in the factory so that only a small number ofnon-critical connections need be made at the point of installation,which can be carried out reliability by tradesmen not specificallytrained for such installations.

This task is solved according to the invention by the supply unitdescribed hereinafter.

In the supply unit according to the invention the physical position ofthe various parts is determined in the factory.

On site only the connections to the fixed supply pipes in the buildingand the electrical mains network are required. If the supply unitconsists of several superimposed components some of the internalconnections must be made after the components are superimposed but theseare non-critical, straight connections.

As a result, a supply unit according to the invention is no moreexpensive than a conventional installation because the cost of the framecarrying the compressor and the suction unit, manufactured in series inthe factory, is easily compensated for by the savings involved in thereduced installation work on site.

Thus the solution provided by the invention also has the benefit thatthe installation space required is reduced. This is particularlybeneficial in applications where no spacious cellar is available. Alsomaintenance and repair of the unit according to the invention is easierand faster because the engineer is always dealing with the same unit anddoes not first have to check the layout of each installation.

In a supply unit according to another embodiment it is also possible toprovide an air storage tank and/or a dry air unit within the same smallspace. Even this supply unit is very easy to install.

The further design of the invention according to another embodiment isadvantageous due to the easy manufacture of the frame carrying the unitand consisting of largely identical components.

The further design of the invention according to another embodiment isbeneficial due to the low production costs and the attractive appearanceof the vertical frame.

A supply unit according to another embodiment has no sharp edges and anattractive appearance.

The further design of the invention according to another embodiment verysimply provides sound insulation for the supply unit. This makes itpossible to install the attractive supply unit in a room within thedental surgery or laboratory if no cellar or separate room is available.

The further design of the invention according to another embodimentmakes it possible to very easily secure the panel components or mountingplates for electronic or fluid trays anywhere on the frame.

The further design of the invention according to another embodiment isof benefit due to the particularly easy installation of the side panelcomponents on the frame.

In a supply unit according to another embodiment it is very easilypossible to attach additional mountings for ancillary electrical orfluid units on the inside rear part of the frame.

The further design of the invention according to another embodiment isof benefit due to the particularly easy connection of base plates andvertical frames.

The further design of the invention according to another embodimentserves for a particularly shear-resistant connection between theprofiles and the base plates.

In a supply unit according to another embodiment it is possible tosecure the fluid lines and electrical cables tidily to the frame awayfrom the heat generating machines.

The further design of the invention according to another embodiment isof benefit due to the clear layout of the internal installations.

A supply unit according to another embodiment can be transportedparticularly easily since the individual components with the units theycarry can easily be carried by two fitters. Storage is also simplified.The combination required for the specific application can easily beproduced with components consisting of different units.

The further design of the invention according to another embodiment isof benefit due to the cost-effective production of the supply unitframe. The side walls also increase the stability of the base plates andthe cover plates.

The further design of the invention according to another embodimentguarantees in a simple manner the correct alignment of superimposedcomponents in the supply unit.

In a supply unit according to another embodiment there are two paralleltracks at the same height on the underside of a base plate upon which acomponent can easily be moved on the cover plate of the component belowit until the panels of the base plate of the upper component enter theopenings in the cover plate of the lower component, thus aligning thecomponents together.

In a supply unit according to another embodiment further fluid lines andelectrical cables can be laid from one level to another near the edge ofthe frame.

In a supply unit according to another embodiment it is very easy tomaintain and test the storage tank. This can simply be pivoted out ofthe interior of the frame, for example, for the pressure safety testwhich is required periodically.

In a supply unit according to another embodiment it is easily possibleto remove the storage tank completely from the frame after it has beenpivoted out.

In the supply unit according to the invention there are aligned openingsin the various base plates and cover plates which serve not only forlaying the fluid lines but also as a ventilation duct once the panels onthe frame have been closed. If the top of the frame is also closed by acover plate, the heat generated by the various units can very easily bedispersed with the aid of this ventilation duct, according to anotherembodiment.

The further design of the invention according to another embodimentprovides operation of the ventilation fan under temperature control.

The further design of the invention according to another embodiment isof benefit concerning vibration-free and therefore low noise operationof the supply unit.

The following section describes the invention in more detail with theaid of the design examples and reference to the drawing. The drawingshows:

FIG. 1: Top view of the front panel of a compressed air andunderpressure supply cabinet for a dental surgery, consisting of threesuperimposed components.

FIG. 2: Top view of the front panel of the supply cabinet according toFIG. 1 after removing the front panels.

FIG. 3: Enlarged top view of a profile used as a vertical frame in thecabinet components of the supply cabinet according to FIGS. 1 and 2.

FIG. 4: View of the underside of a base plate for the cabinet componentsaccording to FIGS. 1 and 2 in a scale larger than in FIGS. 1 and 2 butsmaller than in FIG. 3.

FIG. 5: View of the underside of a cover plate of a cabinet componentmatching the base plate according to FIG. 4.

FIG. 6: Longitudinal section through the base plate according to FIG. 4and the cover plate below this according to FIG. 5 of a lower section ofthe cabinet along the line VI--VI of FIG. 4 or 5 respectively.

FIG. 7: View of a punched metal part which can be used to produce boththe base plate according to FIG. 4 and the cover plate according to FIG.5.

FIG. 8: View of two corners of the frame of a cabinet component afterremoval of its cover plate.

FIG. 9: Similar view as FIG. 8, whereby the side panels are fitted inthe frame and a control unit is also mounted on the frame, and

FIG. 10: Similar view to FIG. 8 but depicting different versions of theinstallation.

FIGS. 1 and 2 show a supply unit in the form of a cabinet for dentalsurgeries consisting of three superimposed supply units (12, 14 and 16).Each of the supply units has a frame designated in total as (18)consisting of a base plate (20), a cover plate (22) and four verticalprofiles (24) connecting these plates. The design and connection of thebase plates, cover plates and profiles are described in more detailbelow.

The base plate (20) of the uppermost supply unit (16) carries two pistoncompressors (26, 28) each of which has an electric motor (30) and twocylinders (34, 36) mounted in a 90° V-shape configuration on a crankcasing (32). As shown in the drawing, the motor shafts are vertical andthe two piston compressors are mounted on the highest base plate (20) sothat their cylinders (34, 36) are symmetrical to the centre axis of thesupply unit (16).

The middle supply unit (14) has on its base plate (20) a suction unit(38) which possesses an electric motor (40) and a fan (42) which isflange-mounted to the motor. The shaft of the electric motor (40) isagain vertical.

In the lower supply unit (16) there is a compressed air storage tank(44) onto which hinges (46, 48) are welded and mounted on hinged bolts(50, 52). The latter are fitted in angle sections (54, 56) which arebolted to the lefthand front profile (24).

A cylindrical dry air unit (62) is held by support rings (58, 60) boltedto the righthand rear profile (24) of the supply unit (12). The dry airunit contains a drying agent which can be regenerated, such as silicagel, for example, and is connected through lines not shown in FIG. 2 toa control unit (64) mounted on the storage tank (44).

The control unit (64) operates generally so that it normally feeds thecompressed air to the storage tank (44) over the drying agent. However,if the treated air has a moisture content above a given value, thecontrol unit pressurises the dry air unit (62) in the opposite directionwith air released from the storage tank (44) and the air containing themoisture is released from the dry air unit (62) into the atmosphere.

A pressure sensor (66) is also shown on the storage tank (44) whichcontrols operation of the piston compressors (26, 28).

As shown in FIG. 2, a compressed air line (68) runs vertically from thepiston compressors (26, 28) through the uppermost base plate (20),through the cover plates and the base plates of the lower supply units(14, 16) and exits from the supply cabinet at the base, where it isconnected to a fixed compressed air line in the building.

A vacuum line (70) and a vent line (72) stretch similarly from thecentre supply unit (14) to the floor of the room in which the supplycabinet is installed. The vacuum line (70) is then connected to a vacuumline in the building and the vent line (72) is connected to a vent lineleading out over the roof of the building.

The openings in the base plates and cover plates to which the variousflow lines (and the electrical cables not shown in FIG. 2 but alsogrouped at the bottom) run also form a ventilation duct to which theheat generated by the suction unit (38) can rise to the uppermost supplyunit (16). The cover plate (22) carries a fan (74) controlled by anadjacent temperature sensor (76). In this way cooling air is drawn bythe fan (74) through the base plate of the lowest supply unit (16) andthrough the supply units (14 and 12).

As shown in FIGS. 1 and 2, the frames (18) of the supply units (12, 14and 16) are enclosed smoothly on all sides by rectangular panels (78) toprovide a cabinet of an attractive appearance together with the visiblepart of the profiles (24) at an angle of 45° to the panels (78).

The front panel (78) of the lowest supply component (16) is angled atits top righthand corner and a triangular panel (80) is permanentlymounted at that point on the frame (18) of this supply component tocarry a main switch (82) and a pressure meter (84).

In comparison to FIG. 1, FIG. 3 shows on a much enlarged scale a frontview of a profile (24). This profile has a front visible panel (68) withside topes (88) recessed at an angle of 45°. At the rear ends there arerear stop panels (90) which serve as a support for the panels (78).

The stops (88, 90) have slots (92, 94) in the centre for mountingfastening components.

The connection points of the stops (88, 90) are connected by a stiffener(96) parallel to the visible panel (86) and the free ends of the rearstops (90) are connected by a stiffener (98). Further stiffeners (100)which are vertical to the visible panel (86) and the stiffener (98)stretch through the connection points of the stops (88, 90). Thisproduces behind the slots (92, 94) channels of a triangular section inwhich nuts for securing bolts or similar can be fitted.

Near the centre of the stiffener (98) there is a first screw channel(102) which reaches over an angle of approximately 300°. Further screwchannels (104, 106) which also reach over approximately 300° areprovided at the ends of two diagonal stiffeners (108) at an angle of+45° and -45° respectively to the stiffener panel (98). Their free endsare connected to the free ends of the stops (90) through furtherstiffeners (110) vertical to the stiffener (98). These each have alongitudinal moulded groove (112) with small longitudinal ribs (114)which serve for fitting the securing screws.

At the rear of the stiffeners (108) there are cable duct panels (116)which have an end section (118) which is in turn folded back through45°, i.e. vertical to the level of the stiffener (98). This end section(118) is formed as a bead and a channel cover plate can be fitted ontoit.

The profile shown in FIG. 3 is in practice produced by cutting from analuminium extrusion. Such aluminium extrusions can be producedcost-effectively. Due to the different stiffeners the profile shown inFIG. 3 provides high stiffness for low weight. Without mechanicalfinishing or with little mechanical reworking (brushing or similar) itprovides an attractive visible surface, forms the side and rear stopsurfaces for the panels, allows easy assembly of the base plates, coverplates and profiles to form a strong frame, produces a cable duct andalso offers facilities for mounting electronic units, fluid units orother ancillary items of equipment which should not be mounted on a baseplate or a cover plate, whether for reasons of temperature, protectionagainst vibration or easy access.

As shown in FIG. 4, the base plate (24) have low side walls (120) turnedupwards which in turn have a return leg (122) parallel to the baseplate. The side panels (120) do not reach into a corner zone where thebase plates (20) are bolted to the vertical profiles (24). For thispurpose three recessed holes (124) are provided in this corner zone inthe same layout as the screw channels (102-106) in the profiles (24).

Inside the triangle produced by the holes (124) there is a rectangularhole (126) which, when the profile is bolted on, is aligned with theadjacent cable channel through the panels (116).

The base plate (20) also has a rectangular opening (128) shown at theright in FIG. 4 whose long edge is very close to the side panel (120) atthe right in FIG. 4. At the lefthand edge of the opening (128) a tongueof material (130) is bent downwards.

Similar to the side panel (120) shown at the left in FIG. 4 there isalso a slightly narrower rectangular opening (132) whose inside edgealso has a tongue of material (134) which is bent downwards. Bothtongues of material protrude an equal distance over the underside of thebase plate (24) and form tracks on which the base plate can be moved ona lower cover plate.

Along the upper and lower side wall of the base plate (20) there is anumber of circular holes (136) which can serve to carry smaller tubesand cables, whilst the opening (128) serves for carrying the compressedair line (68) and the large diameter vacuum line (70) and vent line(72). The opening (132) can also be used for pulling smaller tubes andcables through.

If the openings (128, 132 and 135) are empty or only partly occupiedwith tubes or cables in a specific installation, they act as openingsfor cooling air from one supply unit to the next higher unit. As, forexample, is shown clearly in FIG. 4, this therefore allows currents ofcooling air on all sides of the base plates and cover plates, thusguaranteeing all-round cooling of the units mounted on the base plates.The fan (74) already mentioned sets the cooling air in motion.

Various other small openings (138) in the main part of the base plateserve as mounting points for the piston compressors (26, 28), the vacuumunit (38) or other equipment mounted on such a base plate.

As FIG. 5 shows, the cover plate (22) is of very similar geometry to abase plate (comparable parts of the plates have the same reference) andonly the material tongues (130, 134) on the same side are bent like theside panels (120). Furthermore, the material tongues (130, 134) on acover plate (22) are spaced at slightly smaller intervals than those ona base plate, so that the tongues on a base plate can grip the tongueson a cover plate with some slight play, as shown in FIG. 6.

It is therefore possible to produce base plates and cover plates fromthe same punched section (140) as shown in FIG. 7. If this section is tobe used for base plates, only the additional assembly openings (138) areto be provided. If this is not a problem for a cover plate, exactly thesame cut-out can be used for cover plates and base plates. The sidepanels (120) are then formed with this section and the only differencebetween the cover plates and the base plates is that on a cover platethe material tongues (130, 134) are bent to the same side as the sidepanels (120) and on a fold line which lies approximately one thicknessof the material further inward than on the base plates where thematerial tongues (130, 134) are bent towards the side away from the sidepanels (120).

FIG. 8 shows two corner connections of a frame (18) at a base plate(20).

Self-tapping countersunk metal screws (142) are fitted in the screwchannels (102-106) and their heads reach the underside of the base plate(20) and disappear in the countersunk holes (124).

FIG. 8 clearly shows the configuration of the profiles (24) at thecorners of the base plate (20) without the side panels (120). One canalso clearly see the alignment of the openings (126) in the cable ductproduced by the cable duct panels (116, 118).

The lower section of FIG. 9 shows details of the mounting of the outerpanels (78) on the profiles (24).

A strip (144) with tapped holes (148) is inserted into the triangularchannel behind the slot (92). Two holding lugs (148) are screwed intothe tapped holes (146) spaced vertically and a flanged section (150) issupported on the outside of the stop panel (88). The holding lugs (148)fit with slight play in a bayonet slot (152) which has open end notshown in FIG. 9 so that the outer panel (78) can be lifted and removedby pulling it forwards from the frame (18). As shown, the bayonet slot(152) is provided in a plastic component (154) which is fitted in a sidepanel (156) of the flat shell (158) of the panel (78). Inside the shell(158) there is a mat of sound installation (160).

A mounting plate (162) is fitted at the righthand side panel of thesupply unit shown in FIG. 9. This has ends which are bent through 45° tothe level of the panel which lie in front of the stiffeners (110).Self-tapping screws (166) are fitted in the grooves (112) of thestiffener panels (110). In this way the mounting plate (162) is easilyaccessible directly adjacent to the side panel of the supply unit.

In the design example considered here the mounting plate (162) carriesan electrical control unit (168) supplied with power through a cable(170) fed through the cable channel closed by the front profile (124)and leading down to the in-house installation, and also supplied with aload, for example the electric motors (30) or the electric motor (40),through a cable (172) in the supply component. It is understood that inanalogy also fluid or purely mechanical units can be mounted on theframe (18) to be easily accessible.

FIG. 9 also shows a cover strip (174) made of a flexible plasticmaterial on the cable duct of the front profile (24).

FIG. 10 shows a further possibility for fitting ancillary equipment tothe upper profile (24):

Two mounting plates (78) are fitted to the side stiffener panels (110)through pairs of self-tapping screws (176) fitted in the grooves (112).At the free ends of the mounting plates (178) a stop (182) for the uppersupport ring (58) to which the dry air unit (62) is attached is fixed bymeans of threaded bolts (180). A similar fastening is provided for thelower support ring (60).

It is clear that such a fastening can easily be fitted at any height onone of the profiles (24) without this having to be machined in any way.

If the mounting is to carry a light weight only, just a single mountingplate can be used.

The large diameter ventilation line (72) is visible in the opening (128)shown in the lower section of FIG. 10. A tube (136) which can, forexample, supply cooling water to the dry air unit (62) is also shown inone of the openings (136).

The supply units (12, 14 and 16) are fitted with their equipment in thefactory. Also all pressure lines and electrical cables are fitted in thefactory with the exception of the short vertical connection leadsinterconnecting the supply units or connecting them to the in-houseinstallation.

Thus at the point of installation only the supply units (12, 14 and 16)need be positioned accordingly and the vertical connections providedbetween the components and the in-house installation.

In a modification of the design example described above, the compressedair line (68), the vacuum line (70) and the ventilation line (72) aswell as the electrical connection cables can also be fed upwards throughthe cover plate (22) of the supply unit (16) to the appropriate fixedconnection points in the cabinet.

For applications in which sound insulation and/or an attractiveappearance of the supply unit is less important it is also possible toleave the panels (78) off the cabinet. The supply unit modified in thisway is still characterised by a clear, clean and simple layout.

In a further version of the invention the profiles (24) can runcontinuously from the bottom to the top for low power supply units andthe therefore lighter vacuum unit (38) and a single low power pistoncompressor (26) can be installed on base plates which are supported onthe continuous profiles (24), for example by using brackets which arefitted at the relevant height to the profiles (24) through self-cuttingscrews in the grooves (112).

We claim:
 1. A compressed air and reduced pressure supply unit fordental working places comprising(a) a compressor unit (26, 28), (b) asuction unit (38); (c) a frame (18) upon which said compressor andsuction units are mounted, said frame (18) comprising(1) a first baseplate which carries said compressor unit (26, 28), (2) a second baseplate spaced away from said first base plate and which carries saidsuction unit (38), (3) a plurality of wall panels (78) disposed at rightangles to said base plates, (4) vertical posts connecting said spacedapart first and second base plates, each said vertical post comprisingan extruded metal profile that includes(i) a visible exterior wall (86),(ii) first abutment walls (88) extending at an angle of 45° with respectto said visible exterior wall (86) and at an angle of 90° with respectto each other, which abutment walls (88) cooperate with the verticalside edges of said wall panels (78), and (iii) second abutment walls(94) that are disposed at an angle of 90° with respect to said firstabutment walls (88) and which cooperate with an interior surface of saidwall panels (78).
 2. A supply unit according to claim 1, wherein thatthe wall panels comprise trough-shaped shell members and have insulationmats contained therein.
 3. A supply unit according to claim 1 whereinsaid metal profiles have stiffening webs extending from free edges ofthe second abutment walls in rearward direction being perpendicular tothe visible front wall, the stiffening webs being formed withlongitudinal channels for fasteners.
 4. A supply unit according to claim1 wherein a storage tank is mounted on one of the vertical metalprofiles through vertical hinges for movement between an operatingposition, wherein the storage tank is located within the contour of theframe, and a service position, wherein the storage tank projects fromthe frame.
 5. A supply unit according to claim 1 wherein the base platesare identical in shape.
 6. A supply unit according to claim 1 whereinthe said abutment walls are formed with slots receiving fastenersconnecting wall panels to the vertical posts.
 7. A supply unit accordingto claim 6 wherein the wall panels comprise bayonet slots cooperatingwith lugs of the fasteners mounted in the slots of the abutment walls.8. A supply unit according to claim 1 wherein said metal profiles areformed with at least one screw channel and in that ends of the verticalposts are connected to an associated base plate by means of screwsengaging in adjacent ends of the screw channels.
 9. A supply unitaccording to claim 8 wherein the metal profiles are formed with threescrew channels, the connection lines of which form an isosceles righttriangle.
 10. A supply unit according to claim 1 wherein the rear ofeach metal profile is formed with duct webs forming a cable duct and thebase plates have openings lying between these duct webs.
 11. A supplyunit according to claim 10, wherein free ends of the duct webs areclosed by a removable cover.
 12. A supply unit according to claim 1wherein frame subunits are formed by a lower base plate and a cover baseplate which are connected through vertical posts and the frame is formedby a stack of such frame subunits.
 13. A supply unit according to claim12 wherein a plurality of circular holes are arranged along an edge ofthe base plates and the cover plates.
 14. A supply unit according toclaim 12 wherein the uppermost cover plate carries a fan.
 15. A supplyunit according to claim 14 wherein the fan is controlled by atemperature sensor suspended below the uppermost cover plate.
 16. Asupply unit according to claim 12 wherein the base plates and coverplates are sheet metal parts formed with low side walls, the cornerportions of the base plates and cover plates having no such side walls.17. A supply unit according to claim 16 wherein rectangular tongues areformed integral to one of the longitudinal edges of the openings of thebase plates and the cover plates are bent out of the plane of therespective plate in opposite direction and the tongues of a base plateand of a cover plate are offset approximately by the thickness of thematerial so that one of the tongues overlies the other tongue when theframe subunits are stacked one onto the other.
 18. A supply unitaccording to claim 17 wherein the base plates and the cover plates havesecond openings opposite to those openings through which the fluid linesand electrical cables pass, the tongues belonging to the fluid line andcable receiving openings and the second openings being of the sameheight.